Corkscrew



FIG. 1 is a front elevational view of a corkscrew showing my new design, the rear view being identical thereto;

FIG. 2 is a side elevational view, the opposite side being identical thereto;

FIG. 3 is a top plan view thereof; and

FIG. 4 is a bottom plan view thereof. 

The ornamental design for a corkscrew, as shown and described. 